All three judges agreed that the Senate is only in recess when it has adjourned sine die (Latin for “without a day,” i.e. without setting a date to meet again). This happens only at the end of the first session of a Congress when the second session will begin (as per Amendment XX, Sec. 2) on the next January 3rd, or at the end of the second session, when a newly elected Congress will assemble on that date.
After Congress has adjourned sine die, the President can only call it back into session.
Further, two of the judges ruled that in order for the President to exercise the recess appointment power, the vacancy must have come about during the recess following a sine die adjournment, not merely happen to exist during such a recess. The third judge, while expressing some sympathy for this interpretation, thought that it did not have to be reached in order to decide this case and therefore shouldn’t have been part of the decision.
Assuming this decision holds up—and it is powerfully argued—President Obama’s overreach here has had the effect of severely limiting his power to make recess appointments.
It will be far more constrained than the power such presidents as Eisenhower and George W. Bush exercised. Indeed, since Congress is now in session most of the year, unless the vacancy occurs in the month of December, after Congress has gone home for the year, he no longer has any recess appointment power.
Serves him right.